This invention relates to treatments and compositions of sulfonic acids and their derivatives, particularly to sulfonic acids and their derivatives with improved odour and colour characteristics.
Methods and treatments have been proposed which improve the characteristics of sulfonic acids and their derivatives. U.S. Pat. No. 4,153,627 describes sulfonic acids which contain at least 1% by weight of an olefin with improved thermal and colour stability of the acids and reduced sludge and sulfuric acid content. Indeed, the olefins disclosed in above specification U.S. Pat. No. 4,153,627 are derived from propylene and butene oligomers, such as trimers and, tetramers of propylene. EPA-520 808 describes a sulfonic acid treatment with unsaturated hydrocarbon having a number average molecular weight between about 600 and 3000. However, the above specifications do not report the effect of unsaturated hydrocarbon structure on sulfonic acid purification. Furthermore, the above specifications do not disclose the treatment of sulfonic acids and their derivatives with selective types of unsaturated hydrocarbons to resolve problems of odour and colour. In particular, the problem of high H.sub.2 S and mercaptan content of the sulfonic acid and their derivatives have not been addressed. High H.sub.2 S and mercaptan content give rise to undesirable odour.
It is found, according to this invention, that particular types of unsaturated hydrocarbons can be used to selectively control the colour and odour characteristics of the sulfonic acids and their subsequent derivatives. Thus, one skilled in the art can now improve the colour and odour characteristics of sulfonic acids and their derivatives while maintaining the known advantages of sludge and sulfuric acid reduction and good thermal stability.